Leukapheresis products in multiple myeloma: lower tumor load after mobilization with cyclophosphamide plus granulocyte colony-stimulating factor (G-CSF) compared with G-CSF alone

High-dose therapy with autografting of peripheral blood stem cells (PBSCs) has become an accepted treatment modality. However, gene-marking studies in patients with acute myeloid leukemia and neuroblastoma have revealed that malignant cells reinfused along with leukapheresis products (LPs) contribute to relapse. Thus, a reduction in the number of malignant cells in autografts is desirable. We analyzed the percentage of malignant cells and the number of CD34+ PBSCs in LPs mobilized by granulocyte colony-stimulating factor (G-CSF) alone (LP-S) compared with high-dose cyclophosphamide plus G-CSF (LP-CY) in patients with multiple myeloma (MM). A quantitative polymerase chain reaction assay involving CDR3-specific primers based on the method of limiting dilutions was used to determine the tumor loads of LPs. Sixteen LPs from eight patients with MM were analyzed intraindividually in matched pairs. The percentage of malignant cells was lower in LP-CY (p = 0.017; median 0.0067 vs. 0.009%), whereas the number of CD34+ cells was higher (p = 0.012; median 0.3 vs. 0.095%). The calculated number of malignant cells per CD34+ cell was significantly lower in LP-CY as well (p = 0.017). We conclude that mobilization by cyclophosphamide plus G-CSF leads to a lower number of malignant cells per CD34+ cell in LPs compared with G-CSF alone.

First and second apheresis in patients with multiple myeloma: no differences in tumor load and hematopoietic stem cell yield

Autologous peripheral blood stem cells (PBSC) are now widely used to support myeloablative therapy in patients with multiple myeloma (MM). The presence of malignant cells in these autografts has been demonstrated. Characteristic kinetics with differential and concomitant mobilization of CD34+ and malignant cells after high-dose (HD) chemotherapy and hematopoietic growth factor administration have been reported. We determined the amounts of tumor cells and PBSC in leukapheresis products (LP) collected on day 1 (LP1) and 2 (LP2) from 16 MM patients harvested after HD chemotherapy and G-CSF. Furthermore, LP from six patients collected on day 5 (LP5) could be examined. The content of clonotypic cells was quantitated by an allele-specific oligonucleotide (ASO)-PCR assay based on limiting dilutions. CD34+ PBSC were determined by flow cytometry. The percentages of malignant cells in the leukapheresis products were in the range of 0% to 0.713% (mean 0.047%). CD34+ cells ranged between 0.06% and 5.4% (mean 1.23%). Comparing LP1 with LP2, no differences in the quantity of tumor cells (mean 0.0538% vs 0.0448%; P = 0.96) and CD34+ cells (mean 1.49% vs 1.33%; P= 0.50) were seen. The calculated number of tumor cells per CD34+ cell did not differ significantly (mean 0.0420 vs 0.0249; P = 0.65). Analyzing LP5 revealed no changes in the number of tumor cells per CD34+ cell (0.0511 vs 0.1044; P = 0.46) indicating a relatively constant ratio of PBSC to tumor cells during the course of PBSC harvesting. These results offer the possibility of combining LP harvested over several days without increasing the tumor load per CD34+ cell.

Decreased numbers of circulating B cells in myeloma patients with reduction after conventional chemotherapy

Reports of high numbers of circulating monotypic B cells in patients with multiple myeloma (MM) have recently been published. These cells, which were identified by their expression of CD19, were reported to be resistant to conventional chemotherapy and to represent the source of relapse. We examined blood samples from 48 patients before and 53 patients after glucocorticoid containing chemotherapy by dual color flow cytometry. The absolute count of CD19+B cells in patients before treatment (212.6+/-24.8 x 10(6)/l) was decreased compared to normal controls (P = .038). In the post-treatment group, circulating B cells were highly significantly lower than in untreated patients (45.23+/-6.69 x 10(6)/l. P < .001). This reduction was also seen in 26 patients, that were followed during chemotherapy. The cytoplasmic kappa/lambda ratio was within normal range before and after treatment with no difference according to the light chain isotype of the paraprotein. We conclude that circulating B cells are not increased in patients with MM, that the majority of these cells are polyclonal, and that conventional chemotherapy effectively reduces circulating B cells without leading to dominance of resistant monotypic cells.

A rationale for positive selection of peripheral blood stem cells in multiple myeloma: highly purified CD34+ cell fractions of leukapheresis products do not contain malignant cells

In multiple myeloma (MM), the presence of tumor cells in leukapheresis products (LP) has been demonstrated with highly sensitive molecular biological tools in up to 100% of cases. Therefore methods to reduce the tumor load of LP by CD34+ selection are envisaged. However, there is controversy as to whether the CD34+ cell is already involved in the malignant process. We have established a PCR assay with allele-specific oligonucleotide primers (ASO) complementary to the CDR3-hypervariable region of the immunoglobulin heavy chain gene of each patient's myeloma clone. Using this ASO-PCR, 43 LP of 10 patients with MM eligible for high-dose therapy were assessed for malignant cells. Furthermore, in an experimental setting we have examined 10 CD34+ and four CD19+ fractions obtained from PCR-positive LP by sequential preparative magnetic and fluorescence activated cell sorting (purity >96%) for the presence of the tumor-specific CDR3 region. The majority of LP harbored cells of the myeloma clone (93%), while all CD34+ fractions were PCR-negative. In all CD19+ fractions malignant cells were detected. These results confirm that CD34+ selection can be considered for LP in MM. The sensitivity of the ASO-PCR (up to 10[-5]) enables us further to monitor the efficacy of CD34+ enrichment protocols in the clinical setting.

High-dose chemotherapy in multiple myeloma

The median survival of conventionally treated patients with multiple myeloma is 3 years. Modifications of conventional chemotherapy have failed to show an improved survival rate in most randomized trials. Therapy regimens with dose-escalated alkylating agents (ie melphalan) have induced higher remission rates in comparison to conventional treatment modalities. With the support of autologous or allogeneic hematopoietic progenitor cells, it has been possible to reduce the hematoxicity of these dose-escalated treatments. The transplantation of autologous peripheral blood progenitor cells results in faster hematopoietic reconstitution with decreased high-dose therapy-related morbidity compared to autologous bone marrow. The randomized French myeloma trial and the pair-mate analysis of the results of the 'total therapy' including double autografting of the Barlogie group with data from the South Western Oncology Group (SWOG) showed a significant survival advantage for patients following autologous transplantation. Although a graft-versus-myeloma effect was described, the benefit of high-dose treatment with allogeneic transplantation is less clear, mainly due to the high transplantation-related mortality rate. In this paper, results of transplantation trials are summarized. Prognostic factors and future treatment modalities for myeloma are discussed.

A novel Xenopus homologue of bone morphogenetic protein-7 (BMP-7)

We identified a Xenopus gene closely related to mammalian bone morphogenetic protein (BMP)-7 (also termed osteogenic protein-1 or OP-1). It resembles the mammalian gene in primary structure and expression pattern much more closely than does a previously described Xenopus homologue, originally termed XBMP-7 [Nishimatsu, Suzuki, Shoda, Murakami and Ueno (1992) Biochem. Biophys. Res. Commun. 186, 1487-1495]. The novel gene has therefore been designated XBMP-7 and the gene described earlier has been renamed XBMP-7R (M. Moos and N. Ueno, unpublished work). It has a broad distribution, primarily in the anterior and posterior ventral regions during gastrulation, subsequently becoming prominent at different stages in a wide variety of structures (eyes, neural structures, heart, pronephros, posterior ventral region and other structures), paralleling the distribution of XBMP-4 closely. However, its expression begins later than that of XBMP-4 during gastrulation. Lithium treatment of embryos concentrates the XBMP-7 expression in the expanded eye and heart structures. Ventral overexpression of XBMP-7 produces large protrusions that ultimately develop colouration characteristic of haemoglobin, which is confirmed by markedly expanded expression of alpha-globin. Dorsal overexpression suppresses dorsal anterior structures. Molecular analysis of animal caps overexpressing XBMP-7 reveals induction of markers associated with ventral and haematopoietic tissue, which is consistent with whole-embryo overexpression results. Globin induction by XBMP-7 can be blocked by a truncated BMP receptor previously shown to interrupt BMP-4 signalling, indicating XBMP-7 also interacts with this receptor. Our data support the concept that XBMP-7 may play a variety of roles during embryogenesis, and suggest a possible role in haematogenesis.

The cysteine-rich frizzled domain of Frzb-1 is required and sufficient for modulation of Wnt signaling

Convincing evidence has accumulated to identify the Frizzled proteins as receptors for the Wnt growth factors. In parallel, a number of secreted frizzled-like proteins with a conserved N-terminal frizzled motif have been identified. One of these proteins, Frzb-1, binds Wnt-1 and Xwnt-8 proteins and antagonizes Xwnt-8 signaling in Xenopus embryos. Here we report that Frzb-1 blocks Wnt-1 induced cytosolic accumulation of beta-catenin, a key component of the Wnt signaling pathway, in human embryonic kidney cells. Structure/function analysis reveals that complete removal of the frizzled domain of Frzb-1 abolishes the Wnt-1/Frzb-1 protein interaction and the inhibition of Wnt-1 mediated axis duplication in Xenopus embryos. In contrast, removal of the C-terminal portion of the molecule preserves both Frzb-Wnt binding and functional inhibition of Wnt signaling. Partial deletions of the Frzb-1 cysteine-rich domain maintain Wnt-1 interaction, but functional inhibition is lost. Taken together, these findings support the conclusion that the frizzled domain is necessary and sufficient for both activities. Interestingly, Frzb-1 does not block Wnt-5A signaling in a Xenopus functional assay, even though Wnt-5A coimmunoprecipitates with Frzb-1, suggesting that coimmunoprecipitation does not necessarily imply inhibition of Wnt function.

Cellular UDP-glucose deficiency caused by a single point mutation in the UDP-glucose pyrophosphorylase gene

We previously isolated a mutant cell that is the only mammalian cell reported to have a persistently low level of UDP-glucose. In this work we obtained a spontaneous revertant whose UDP-glucose level lies between those found in the wild type and the mutant cell. The activity of UDP-glucose pyrophosphorylase (UDPG:PP), the enzyme that catalyzes the formation of UDP-glucose, was in the mutant 4% and in the revertant 56% of the activity found in the wild type cell. Sequence analysis of UDPG: PP cDNAs from the mutant cell showed one missense mutation, which changes amino acid residue 115 from glycine to aspartic acid. The substituted glycine is located within the largest stretch of strictly conserved residues among eukaryotic UDPG:PPs. The analysis of the cDNAs from the revertant cell indicated the presence of an equimolar mixture of the wild type and the mutated mRNAs, suggesting that the mutation has reverted in only one of the alleles. In summary, we demonstrate that the G115D substitution in the Chinese hamster UDPG:PP dramatically impairs its enzymatic activity, thereby causing cellular UDP-glucose deficiency.

Frzb-1, an antagonist of Wnt-1 and Wnt-8, does not block signaling by Wnts -3A, -5A, or -11

Frzb-1 is a secreted factor that was recently shown to inhibit signaling by Wnts 1 and 8. Frzb-1 contains an amino terminal domain that is homologous to the Drosophila polarity gene frizzled; several other secreted proteins that share this feature have now been identified. These findings raise the question of whether or not Frzb-1 is a general inhibitor of signaling by all Wnts. We show that signaling of Wnts -3A, 5A, and 11 is not blocked by Frzb-1, demonstrating that Frzb-1 can discriminate both between the principle functional Wnt classes that have been proposed and within them.

A quantitative PCR assay for the detection of low amounts of malignant cells in multiple myeloma

BACKGROUND

High-dose chemotherapy (HDT) with autografting of hematopoietic stem cells induces up to 50% of complete remissions in patients with multiple myeloma. Cases of molecular remissions have been reported. However, qualitative assays determine only the absence or presence of a monoclonal population depending on their sensitivity. Therefore reliable and sensitive methods to quantitate tumor loads are necessary.

MATERIALS AND METHODS

We have established a quantitative PCR assay (qPCR) with allele-specific primers complementary to hypervariable CDR3 regions. Sample DNA was serially diluted in 0.5 log steps and amplified in 10 replicates. PCR results were analysed by likelihood maximization and chi 2 minimization to calculate the tumor load.

RESULTS

Three approaches were taken to validate the qPCR. 1) Single copies of the CDR3 region of U266 cells could be detected. 2) Analysis of a bone marrow sample by FACS for CD 38+2 and kappa/lambda restricted plasma cells and by qPCR yielded results of 1.4 and 2.5% respectively. 3) qPCR results with plasmids carrying CDR3 regions simulating different tumor loads diverged by no more than a factor of 1.6 from the expected values.

CONCLUSION

We consider the qPCR to be an accurate method for assessing samples with low amounts of malignant cells.

Delineation of the catalytic domain of Clostridium difficile toxin B-10463 to an enzymatically active N-terminal 467 amino acid fragment

In an attempt to directly approach the postulated toxic domain of Clostridium difficile's TcdB-10463, eight subclones of different size and locations in the N-terminal third of the toxin were generated. Expression of these toxin fragments was checked in Western blots and the enzymatic activity of the expressed proteins was analyzed by glucosylating Ras related small GTP-binding proteins. Two polypeptides of 875 aa (TcdBc1-3) and 557 aa (TcdBc1-H) glucosylated their targets Rho, Rac and Cdc42 with the same activity and specificity as the holotoxin. In comparison 516 aa (TcdBc1-N) and 467 aa (TcdBc1-A) protein fragments exhibited highly reduced activity, while Tcdc1 and TcdB2-3 (aa 1-243 and 244-890, respectively) were enzymatically inactive. Our results indicate that all structures involved in the catalysis are located at several different sites within the 557 aa fully active fragment. The shortest enzymatically still active protein covers aa 1-467 and obviously fulfils all minimal requirements for glucosylation. The data support the postulated three domain model of 'large clostridial cytotoxins'.

Lack of t(14;18) polymerase chain reaction-positive cells in highly purified CD34+ cells and their CD19 subsets in patients with follicular lymphoma

Follicular lymphoma (FL) is characterized in a significant proportion of cases by the t(14;18) chromosomal translocation, which results in the juxtaposition of the oncogene bcl-2 to the joining region of the immunoglobulin heavy chain (IgH) gene. Molecular sequence analysis indicates that the t(14;18) rearrangement occurs in a B-lymphoid progenitor cell at the time of IgH rearrangement. We were interested whether hematopoietic stem and progenitor cells as characterized by CD34 expression bear the translocation. Bone marrow (BM)-CD34+ cells were enriched from 14 patients with FL whose BM was known to be positive for bcl-2/IgH (major breakpoint region [MBR]). Six patients were in complete remission (CR), two patients were in partial remission (PR), and six patients had active disease. Six patients had histological BM involvement when the samples were obtained. Using an immunomagnetic selection device (MINI-MACS), a mean purity of 88.7% +/- 4% CD34+ cells was achieved. The CD34+ cells were further enriched by fluorescence activated cell sorting (FACS) using CD34 fluorescein isothiocyanate (FITC)- and CD19 phycoerythrin (PE)-conjugated antibodies. The IgH gene was rearranged in the CD34+/CD19+ cell subset of all patients assessed by polymerase chain reaction (PCR). This population is thought to represent the progenitor stage at which the bcl-2/IgH translocation occurs. The unseparated BM mononuclear cell fraction from all 14 patients was positive for bcl-2/IgH using a nested PCR, but the BM-CD34+ cell fraction and the respective CD34+/CD19+ subset were negative in 13 of these 14 patients. The one patient with a positive PCR signal in the CD34+ cell subset had a relapse with BM involvement. We conclude that CD34+ progenitor cells including CD34+/CD19+ B-cell progenitors are not involved in the malignant cell clone. These data are in agreement with a transgenic mouse model, which indicates that the malignant phenotype in FL is sustained by mature B cells.

Frzb, a secreted protein expressed in the Spemann organizer, binds and inhibits Wnt-8

We isolated a Xenopus homolog of Frzb, a newly described protein containing an amino-terminal Frizzled motif. It dorsalized Xenopus embryos and was expressed in the Spemann organizer during early gastrulation. Unlike Frizzled proteins, endogenous Frzb was soluble. Frzb was secretable and could act across cell boundaries. In several functional assays, Frzb antagonized Xwnt-8, a proposed ventralizing factor with an expression pattern complementary to that of Frzb. Furthermore, Frzb blocked induction of MyoD, an action reported recently for a dominant-negative Xwnt-8. Frzb coimmunoprecipitated with Wnt proteins, providing direct biochemical evidence for Frzb-Wnt interactions. These observations implicate Frzb in axial patterning and support the concept that Frzb binds and inactivates Xwnt-8 during gastrulation, preventing inappropriate ventral signaling in developing dorsal tissues.

Primary structure and tissue distribution of FRZB, a novel protein related to Drosophila frizzled, suggest a role in skeletal morphogenesis

Articular cartilage extracts were prepared to characterize protein fractions with in vivo chondrogenic activity (Chang, S., Hoang, B., Thomas, J. T., Vukicevic, S., Luyten, F. P., Ryba, N. J. P., Kozak, C. A., Reddi, A. H., and Moos, M. (1994) J. Biol. Chem. 269, 28227-28234). Trypsin digestion of highly purified chondrogenic protein fractions allowed the identification of several unique peptides by amino acid sequencing. We discovered a novel cDNA encoding a deduced 36-kDa protein by using degenerate oligonucleotide primers derived from a 30-residue peptide in reverse transcription polymerase chain reactions. Its N-terminal domain showed approximately 50% amino acid identity to the corresponding region of the Drosophila gene frizzled, which has been implicated in the specification of hair polarity during development. Hydropathy and structural analyses of the open reading frame revealed the presence of a signal peptide and a hydrophobic domain followed by multiple potential serine/threonine phosphorylation sites and a serine-rich C terminus. Cell fractionation studies of primary bovine articular chondrocytes and transfected COS cells suggested that the protein is membrane-associated. In situ hybridization and immunostaining of human embryonic sections demonstrated predominant expression surrounding the chondrifying bone primordia and subsequently in the chondrocytes of the epiphyses in a graded distribution that decreased toward the primary ossification center. Transcripts were present in the craniofacial structures but not in the vertebral bodies. Because it is expressed primarily in the cartilaginous cores of developing long bones during embryonic and fetal development (6-13 weeks) and is homologous to the polarity-determining gene frizzled, we believe that this gene, which we named frzb, is involved in morphogenesis of the mammalian skeleton.

Structural features of a close homologue of L1 (CHL1) in the mouse: a new member of the L1 family of neural recognition molecules

We have identified a close homologue of L1 (CHL1) in the mouse. CHL1 comprises an N-terminal signal sequence, six immunoglobulin (Ig)-like domains, 4.5 fibronectin type III (FN)-like repeats, a transmembrane domain and a C-terminal, most likely intracellular domain of approximately 100 amino acids. CHL1 is most similar in its extracellular domain to chicken Ng-CAM (approximately 40% amino acid identity), followed by mouse L1, chicken neurofascin, chicken Nr-CAM, Drosophila neuroglian and zebrafish L1.1 (37-28% amino acid identity), and mouse F3, rat TAG-1 and rat BIG-1 (approximately 27% amino acid identity). The similarity with other members of the Ig superfamily [e.g. neural cell adhesion molecule (N-CAM), DCC, HLAR, rse] is 16-11%. The intracellular domain is most similar to mouse and chicken Nr-CAM, mouse and rat neurofascin (approximately 60% amino acid identity) followed by chicken neurofascin and Ng-CAM, Drosophila neuroglian and zebrafish L1.1 and L1.2 (approximately 40% amino acid identity). Besides the high overall homology and conserved modular structure among previously recognized members of the L1 family (mouse/human L1/rat NILE; chicken Ng-CAM; chicken/mouse Nr-CAM; Drosophila neuroglian; zebrafish L1.1 and L1.2; chicken/mouse neurofascin/rat ankyrin-binding glycoprotein), criteria characteristic of L1 were identified with regard to the number of amino acids between positions of conserved amino acid residues defining distances within and between two adjacent Ig-like domains and FN-like repeats. These show a collinearity in the six Ig-like domains and four adjacent FN-like repeats that is remarkably conserved between L1 and molecules containing these modules (designated the L1 family cassette), including the GPI-linked forms of the F3 subgroup (mouse F3/chicken F11/human CNTN1; rat BIG-1/mouse PANG; rat TAG-1/mouse TAX-1/chicken axonin-1). The colorectal cancer molecule (DCC), previously introduced as an N-CAM-like molecule, conforms to the L1 family cassette. Other structural features of CHL 1 shared between members of the L1 family are a high degree of N-glycosidically linked carbohydrates (approximately 20% of its molecular mass), which include the HNK-1 carbohydrate structure, and a pattern of protein fragments comprising a major 185 kDa band and smaller fragments of 165 and 125 kDa. As for the other L1 family members, predominant expression of CHL1 is observed in the nervous system and at later developmental stages. In the central nervous system CHL1 is expressed by neurons, but, in contrast to L1, also by glial cells. Our findings suggest a common ancestral L1-like molecule which evolved via gene duplication to generate a diversity of structurally and functionally distinct yet similar molecules.

A role for Rho in receptor- and G protein-stimulated phospholipase C. Reduction in phosphatidylinositol 4,5-bisphosphate by Clostridium difficile toxin B

Receptors coupled to heterotrimeric guanine nucleotide-binding proteins (G proteins) activate phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2)-hydrolyzing phospholipase C (PLC) enzymes by activated alpha of free beta gamma subunits of the relevant G proteins. To study whether low molecular weight G proteins of the Rho family are involved in receptor signaling to PLC, we examined the effect of Clostridium difficile toxin B, which glucosylates and thereby inactivates Rho proteins, on the regulation of PLC activity in human embryonic kidney (HEK) cells stably expressing the m3 muscarinic acetylcholine receptor (mAChR) subtype. Toxin B treatment of HEK cells did not affect basal PLC activity, but potently and efficiently inhibited mAChR-stimulated inositol phosphate formation. PLC activation by the endogenously expressed thrombin receptor and by the direct G protein activators, A1F-4 and guanosine 5'-[gamma-thio]triphosphate (GTP gamma S), studied in intact and permeabilized cells, respectively, were also inhibited by toxin B treatment. C3 exoenzyme, which ADP-ribosylates Rho proteins, mimicked the inhibitory effect of toxin B on GTP gamma S-stimulated PLC activity. Finally both toxin B and C3 exoenzyme significantly reduced, by 40 to 50%, the total level of PtdIns(4,5)P2 in HEK cells, without affecting the levels of phosphatidylinositol and phosphatidylinositol 4-phosphate. Accordingly, When PLC activity was measured with exogenous PtdIns(4,5)P2 as enzyme substrate, Ca(2+)- as well as GTP gamma S- or A1F-4-stimulated PLC activities were not altered by prior toxin B treatment. In conclusion, evidence is provided that toxin B and C3 exoenzyme, apparently by inactivating Rho proteins, inhibit G protein-coupled receptor signalling to PLC, most likely by reducing the cellular substrate supply.

Purification of bovine brain adenylyl cyclase with a novel derivative of forskolin: evidence for a high specific activity form of the enzyme

An improved affinity support for the purification of adenylyl cyclase was prepared from 7-desacetyl-7-aminoethylaminocarbonyl forskolin. This analog allows convenient synthesis of an affinity matrix that is chemically stable, with-standing repeated use for up to two years, and efficient, yielding purifications of adenylyl cyclase from solubilized bovine brain membranes of 2,000-6,000 fold in a single step. Immunoblotting data suggest that the majority of the enzyme purified in this fashion differs from forms described previously. Since the specific activity of this preparation is substantially higher than that described in previous reports, it is possible that the purification described here selects, presumably on the basis of affinity for forskolin, for a form of adenylyl cyclase with higher specific activity than any described previously.

High incidence of a second BCR-ABL fusion in chronic myeloid leukemia revealed by interphase cytogenetic analysis on blood and bone marrow smears

The t(9;22)(q34;q11) is the single most common chromosomal abnormality in leukemias. Recently, dual-color fluorescence in situ hybridization (FISH) protocols for the detection of the BCR-ABL fusion, which is the molecular counterpart of this translocation, have been described. In the present study, we analyzed blood or bone marrow smears of 46 patients (34 with chronic myeloid leukemia [CML] and 12 with acute lymphoblastic leukemia [ALL]) for the presence of a BCR-ABL fusion. On these clinical routine samples, hybridization was performed with high efficiency and the BCR-ABL fusion was detected reliably. This series includes one case with a Philadelphia chromosome (Ph) on banding analysis and negative reverse transcriptase polymerase chain reaction (RT-PCR) results. Surprisingly, in 13 of the 34 CML patients (4 of 17 patients with chronic phase and 9 of 17 patients with blast crisis), and in 1 of the 12 ALL patients, an additional BCR-ABL fusion was diagnosed in 4% to 72.5% of interphase cells. In 10 of these 14 patients, banding data are available; only in two cases was the additional Ph detected by metaphase analysis. The data from this interphase cytogenetic analysis indicate that an additional Ph occurs more frequently than would be assumed based on banding analysis.

High-dose therapy with peripheral blood progenitor cell transplantation in low-grade non-Hodgkin's lymphoma

It was the objective of our study to evaluate the efficacy of a sequential high-dose therapy with peripheral blood progenitor cell (PBPC) support in patients with low-grade non-Hodgkin's lymphoma (NHL). Since July 1991, 48 patients (23 male/25 female) with a median age of 43 years (range 26-55) were included in the study. At the time of entry, 28 patients were in first and seven in second or higher remission. Twelve patients had relapse of disease and one patient had tumor progression. PBPC were collected during granulocyte colony-stimulating factor (G-CSF)-enhanced leukocyte recovery following treatment with high-dose cytarabine and mitoxantrone (HAM). A median of two leukaphereses (range 2-7) resulted in 6.9 x 10(6) CD34+ cells/kg (median, range 2.1 x 10(6)-38.8 x 10(6)). A comparison was made between the harvests obtained from patients in first remission and those from patients in second remission, in relapse or progressive disease. Patients mobilized in first remission tended to have a greater collection efficiency for CD34+ cells comprising a significantly greater proportion of more primitive CD34+/Thy-1+ progenitor cells. Conversely, leukapheresis (LP) products collected during first remission contained a significantly smaller proportion of CD34+/CD45RA+ cells and CD34+/c-kit+ cells, subsets which reflect a more differentiated progenitor cell stage. Following high-dose therapy and PBPC autografting, the median time to reach platelets > or = 20 x 10(9)/l and neutrophils > or = 0.5 x 10(9)/l and 12 and 13 days, respectively. Two patients died of treatment-related toxic organ failure. Thirty-nine patients are alive in remission after a median follow-up time of 15 months (range 1-31), while seven patients relapsed between 5 and 29 months post-transplantation. Except for one patient autografted in first remission, the patients with relapse had a history of previous relapse or progressive disease. Since the probability of disease-free survival appears to be related to the disease status at the time of autografting, PBPC-supported high-dose therapy including total body irradiation should be investigated further for patients with low-grade NHL while they are in first remission.

Successful collection and transplantation of peripheral blood stem cells in cancer patients using large-volume leukaphereses

It was the aim of our study to determine the collection efficiency and yield of CD34+ cells in 88 cancer patients (pts, 44 males/44 females) who underwent 154 large-volume leukaphereses (LV-LPs). The diagnoses were as follows: 18 patients had Non-Hodgkin's lymphoma, 9 Hodgkin's disease, 24 multiple myeloma, 6 acute leukemia, 27 breast cancer, and 4 patients had solid tumors of different types. During the course of LV-LPs, 20 liters (1) of blood were processed at a median flow-rate of 85 ml/min (CS 3000 Baxter) and 130 ml/min (COBE Spectra), respectively. Peripheral blood stem cells (PBSC) were collected following granulocyte colony-stimulating factor (G-CSF)-supported cytotoxic chemotherapy. A 31% and 21% mean decrease in the platelet and white blood count was noted at the end of the LV-LPs when compared with the pre-leukapheresis values. The aphereses were well tolerated without adverse effects. The level of circulating CD34+ cells was closely related to the number of CD34+ cells contained in the respective leukapheresis product (R = 0.89, P < 0.001). Compared with 270 patients who underwent 838 regular 10 1 LPs, the yield of CD34+ cells/kg was almost two-fold greater (4.84 +/- 0.63 x 10(6) [Mean +/- SEM] vs. 2.60 +/- 0.16 x 10(6), P < 0.001). The antigenic profile of CD34+ cells was assessed in 54 separate products collected on the occasion of 27 LV-LPs following the processing of 10 1 and 20 1, respectively. The intra-individual comparison included differentiation- as well as lineage-associated markers (CD38, Thy-1, c-kit, CD33, CD45RA). No difference in the subset composition was observed between the first and second product, arguing against a preferential release of particular CD34+ cell subsets during the procedure. As shown by molecular biological or immunocytochemical examination, the likelihood of harvesting malignant cells using large-volume aphereses was not increased in comparison with regular leukaphereses. Single harvests of > or = 2.5 x 10(6) CD34+ cells/kg could be obtained in 74% of the patients, compared with 52% in case of regular LPs. As the majority of patients were autografted with more than 2.5 x 10(6) CD34+ cells/kg following high-dose therapy, hematological recovery in general was rapid and not related to the type of apheresis product used. Considering patient comfort and savings in resource utilization, large-volume leukaphereses have become the standard procedure for PBSC collection in our center.

Characterization of apple 18 and 31 kd allergens by microsequencing and evaluation of their content during storage and ripening

Patients with tree pollinosis frequently report allergic reactions after ingestion of apples. The severity of apple allergy has been related to the variety of apples and their degree of maturity. To generate a serum pool that is representative of various IgE-binding patterns of apple-allergic sera, serum samples from 34 patients allergic to tree pollens were screened. Only 24 serum samples reacted to the apple extract. Pooled serum was used to identify allergens in apples. An efficient and consistent extraction method for apple fruits was used to compare the immunoreactivities of extracts of different varieties (McIntosh, Red Delicious, Granny Smith, and Golden Delicious) of freshly picked and store-purchased apples. We found that Golden Delicious apples had the greatest amount of the 18 kd allergen, which has been reported to be a potent IgE-binding apple allergen. Store-purchased apples contained higher concentrations of the 18 kd allergen than freshly picked apples. In our study only 37.5% of sera reacted to the 18 kd protein, whereas 75% of the sera reacted to a 31 kd allergen. Other immunoreactive bands in apple extracts included proteins of 50, 38, 16, 14, and 13 kd. The amino-terminal amino acid sequences of the two major allergens, 18 kd and 31 kd, were determined. These sequences shared approximately 50% identity with disease resistance proteins of various plants or Bet v 1 in birch tree pollens. The appearance of various allergens was also investigated in mature apples during storage. The amount of 18 kd allergen increased significantly when apples were stored at 4 degrees C. However, under controlled atmospheric conditions in which oxygen- and carbon dioxide-induced ripening were regulated, the amount of 18 kd allergen remained unaffected. Because ripening and maturation were not associated with increases in 18 kd allergen content, the observed changes might be induced by factors related to disease resistance.

High-dose therapy with peripheral blood progenitor cell support in patients with non-Hodgkin's lymphoma

Between September 1991 and April 1995, high-dose therapy with peripheral blood progenitor cell (PBPC) support was administered to 105 patients with non-Hodgkin's lymphoma (NHL). Thirty-three patients had high-grade NHL, while 72 patients had different forms of low- or intermediate-grade NHL. Except for three patients who received G-CSF during steady-state hematopoiesis, PBPCs were collected following cytokine-supported cytotoxic chemotherapy. This included G-CSF or the sequential administration of interleukin 3 (IL-3) and GM-CSF. Assessing bone marrow (BM) samples before the start of chemotherapy and leukapheresis (LP) products collected during cytokine-enhanced marrow recovery, a 2.3-fold greater mean concentration of CD34- cells was found in peripheral blood (p < 0.005). The blood-derived progenitor cells were enriched with a particular subset of more primitive progenitors, as the mean proportion of CD34+/Thy-1+ cells in LP products was three-fold greater in comparison to premobilization BM samples, respectively (p < 0.001). In contrast, the mean proportion of CD34+/CD19+ and CD19+ cells in LP products was 8.8- and 80-fold smaller compared to BM samples, respectively (p < 0.001). Following high-dose conditioning therapy including TBI in 74 patients, reinfusion of PBPC resulted in rapid and sustained engraftment in the majority of patients, while in seven patients an unsubstituted platelet count of greater than 20 x 10(9)/l was reached between 31 and 51 days. Five patients died of treatment-related complications between 13 and 188 days following transplantation. The probability of long-term disease-free survival at 30 months in patients autografted while they were in first remission was 70% in high-grade and 83% in low-grade NHL, respectively. The data may provide the rationale for the use of PBPC-supported high-dose regimens as first-line treatment for patients at high risk of treatment failure.

Sequential high-dose treatment with peripheral blood progenitor cell transplantation in patients with multiple myeloma

In June 1992, we started a dose-escalated cytotoxic therapy with peripheral blood progenitor cell (PBPC) transplantation in patients with chemosensitive multiple myeloma (MM). At the time of best response to conventional treatment, 70 patients received high-dose cyclophosphamide (HD-CY) or, in case of pre-existing heart disease, dose-escalated ifosfamide/mitoxantrone followed by filgrastim (R-metHuG-CSF, 300 micrograms/day). PBPC collection was commenced when CD34+ cells were detectable using direct immunofluorescence analysis. Fifty-four out of 70 patients were successfully harvested (> or = 2.5 x 10(6) CD34+ cells/kg body weight [BW]) after the first cycle of HD chemotherapy. Conditioning therapy consisted of 140 mg/m2 melphalan plus TBI (14.4 Gy hyper-fractionated) or 200 mg/m2 melphalan in patients not eligible for TBI because of previous radiotherapy. To date, 56 patients have been transplanted. Autografts contained a median of 3.4 x 10(6) CD34+ cells/kg BW. Following reinfusion of PBPC, rapid engraftment was achieved in 54 out of 56 patients with a median of 14 days (range 9-23) to reach 0.5 x 10(9)/l neutrophils and 10 days (range 5-22) for an unsubstituted platelet count of > 20 x 10(9)/l. One patient died of transplantation-related complications. Sequential HD treatment improved the remission status (European Bone Marrow Transplantation criteria) in 19 out of 46 patients (9 patients too early). Of note, in 11 patients the immunofixation became negative and a polyclonal immunoglobulin reconstitution was achieved. Our protocol provides an effective treatment strategy for patients with advanced MM combined with low treatment-related toxicity.

Anti-dorsalizing morphogenetic protein is a novel TGF-beta homolog expressed in the Spemann organizer

We have identified a novel growth factor in Xenopus, which is most closely related to human Bone Morphogenetic Protein-3. Its expression peaks during gastrulation, most prominently in the Spemann organizer, and persists in the posterior neural floor plate and prechordal plate during neurulation. Injection of the corresponding mRNA into dorsal blastomeres results in dose-dependent suppression of dorsal and anterior structures, even in the presence of lithium chloride. Overexpression of the gene downregulates the dorsalizing factors noggin, goosecoid and follistatin, as well as the dorsal markers NCAM, muscle actin and MyoD; conversely, ventral markers are induced. We therefore designate this gene product Anti-Dorsalizing Morphogenetic Protein (ADMP). Though development of dorsoanterior structures is suppressed when exogenous ADMP is injected, the gene is induced by lithium chloride treatment or activin, both of which are known to produce the opposite effect. Thus, the expression of ADMP resembles that of several dorsalizing signals, but its product exerts dorsal-suppressing activity. This suggests that ADMP may moderate organizer-associated dorsalizing influences. These findings are also consistent with the recently advanced proposal of dorsally expressed inhibitory activin-like signals.

Models of risk assessments for biologicals or related products in the European Union

In the context of veterinary biologicals, environmental risk assessment means the evaluation of the risk to human health and the environment (which includes plants and animals) connected with the release of such products. The following categories or types of veterinary biologicals can be distinguished: non-genetically modified organisms (non-GMOs) (inactivated/live) GMOs (inactivated/live) carrier products related products (e.g. non-specific "inducers'). Suitable models used in risk assessment for these products should aim to identify all possible adverse effects. A good working model should lead, at least, to a qualitative judgement on the environmental risk of the biological product (e.g. negligible, low, medium, severe, unacceptable). Quantifiable outcomes are rare; therefore, the producer of a biological product and the European control authorities should accept only models which are based on testable points and which are relevant to the type of product and its instructions for use. In view of animal welfare aspects, models working without animals should be preferred. In recent years, some of these methods have been integrated into safety tests described in European Union Directives and in monographs of the European Pharmacopoeia. By reviewing vaccine/registration problems (e.g. Aujeszky's disease live vaccine for pigs, and vaccinia-vectored rabies vaccine), several models used in risk assessment are demonstrated and discussed.

Detection of minimal residual disease by polymerase chain reaction in B cell malignancies

It was the aim of this study to examine the prognostic value of the detection of minimal residual disease (MRD), with the help of the polymerase chain reaction (PCR), in patients with non-Hodgkin's lymphoma (NHL) and multiple myeloma (MM) who underwent sequential high-dose therapy with peripheral blood progenitor cell (PBPC) support, and in patients with acute myeloid leukemia (AML) of the subclass M4Eo who underwent high-dose consolidation therapy. Basis for the application of a PCR assay in these disease entities are the following specific gene rearrangements: the t(14;18) translocation in a high percentage of NHL, the clonal rearrangement of the Ig heavy chain locus resulting in a unique complementary determining region 3 (CDR3) for MM region and the inversion 16 characteristic for the M4Eo subclass of AML. Before the G-CSF-supported cytotoxic chemotherapy was given, 65% of the 52 patients with low- and intermediate-grade NHL enrolled into the study had PCR+ bone marrow (BM) and/or peripheral blood (PB) samples. The majority of patients (29 of 52) were autografted with a PCR+ transplant. The proportion of harvests containing t(14;18)+ cells was two-fold less in patients mobilized in first remission than in those with a history of previous treatment failure. This was also reflected when examining the B cell contents of the harvests measured as CD19+ cells with a 3.3-fold smaller proportion of CD19+ cells in leukapheresis (LP) products of patients mobilized in first remission. Patients who received a PCR- transplant are in remission and remained PCR- in BM and PB samples post-transplantation. Conversion to PCR-negativity in BM and PB samples post-transplantation was observed in 11 of 19 patients who were also in remission. In contrast, 6 of 29 patients who were autografted with PCR+ products relapsed, while 4 of them presented with PCR- samples on several occasions post-transplantation. In patients with MM, the assessment of MRD in PBPC harvests was based on the CDR3 regions of the Ig heavy chain locus as a marker for clonality. The great majority of LP products (17 out of 19) contained tumor cells. To prove positive enrichment procedures for the elimination of tumor cells, CD34+ and CD19+ cell fractions obtained from LP samples in an experimental setting via preparative flow cytometry were analyzed for MRD resulting in PCR-negativity for all CD34+ fractions. The results of the four patients with AML M4Eo and inversion 16 are preliminary, with a tendency of persistence of PCR-positivity after finishing the high-dose consolidation therapy. In one case, recurrence of disease was accompanied by an increase of the signal strength in the PCR assay. Longer follow-up periods are necessary to determine the prognostic value of these PCR findings in the different disease entities.

DNA sequencing from single phage plaques using solid-phase magnetic capture

Many operations encountered in molecular cloning are labor-intensive and time-consuming. One case that is often troublesome is the subcloning of cDNA clones from lambda gt11 phage into plasmid vectors. In situations where several clones have been isolated, time could be saved by a means of assessing insert size and sequence unambiguously without subcloning, particularly where degenerate PCR or low-stringency hybridization approaches are taken to identify multiple members of a gene family. We describe a simple and reliable strategy for efficient sequencing of small amounts of lambda phage DNA, lysates or individual phage plaques. The strategy combines the advantages of universal lambda phage primers, rapid air thermal cycling, streptavidin magnetic bead capture of highly purified single-stranded templates and the unparalleled clarity of T7 DNA polymerase sequence. We routinely obtain 350-500 bases of unambiguous sequence from each reaction. It takes only hours from lifting phage plaques to finishing the sequencing reactions. The method provides an alternative to thermal cycle sequencing that has comparable sensitivity and affords sequence data of much higher clarity.

Cartilage-derived morphogenetic proteins. New members of the transforming growth factor-beta superfamily predominantly expressed in long bones during human embryonic development

Partially purified extracts from newborn calf articular cartilage were found to induce cartilage and bone when subcutaneously implanted in rats. This activity showed characteristics of bone morphogenetic proteins (BMPs). Degenerate oligonucleotide primer sets derived from the highly conserved carboxyl-terminal region of the BMP family were designed and used in reverse transcription-polymerase chain reactions with poly(A)+ RNA from articular cartilage as template to determine which BMPs are produced by chondrocytes. Two novel members of the transforming growth factor-beta (TGF-beta) superfamily were identified and designated cartilage-derived morphogenetic protein-1 (CDMP-1) and -2 (CDMP-2). Their carboxyl-terminal TGF-beta domains are 82% identical, thus defining a novel subfamily most closely related to BMP-5, BMP-6, and osteogenic protein-1. Northern analyses showed that both genes are predominantly expressed in cartilaginous tissues. In situ hybridization and immunostaining of sections from human embryos showed that CDMP-1 was predominantly found at the stage of precartilaginous mesenchymal condensation and throughout the cartilaginous cores of the developing long bones, whereas CDMP-2 expression was restricted to the hypertrophic chondrocytes of ossifying long bone centers. Neither gene was detectable in the axial skeleton during human embryonic development. The cartilage-specific localization pattern of these novel TGF-beta superfamily members, which contrasts with the more ubiquitous presence of other BMP family members, suggests a potential role for these proteins in chondrocyte differentiation and growth of long bones.

Sequential high-dose therapy with peripheral-blood progenitor-cell support in low-grade non-Hodgkin's lymphoma

PURPOSE

To evaluate the feasibility of a sequential high-dose therapy with peripheral-blood progenitor-cell (PBPC) support in patients with follicular lymphoma.

PATIENTS AND METHODS

Since July 1991, we have included 30 patients (17 men and 13 women) with a median age of 41 years (range, 26 to 55) in the study. At the time of study entry, 17 patients were in first and six in second or higher remission. Another six patients had relapse of disease and one had tumor progression. PBPC were collected during filgrastim-supported leukocyte recovery following high-dose cytarabine (ara-C)/mitoxantrone (HAM).

RESULTS

A median of two leukaphereses (range, one to seven) resulted in a median of 5.7 x 10(6) CD34+ cells/kg (range, 2.9 to 23.7 x 10(6). A distinct population of B-lymphoid progenitors (CD34+/CD19+) was not detectable in the autografts, and the content of CD19+ B cells was remarkably low, comprising a median of 0.07% of the mononuclear cells. Using the polymerase chain reaction (PCR) assay for the major breakpoint regions (MBR) of the bcl-2/immunoglobulin H (IgH) translocation, 22 patients had autografts positive for the t(14;18) translocation, whereas seven patients had PCR-negative transplants. The autograft of one patient could not be assessed. Following myeloablative therapy, hematologic recovery was rapid without cytokine support. The median times to reach a platelet count > or = 20 x 10(9)/L and neutrophil count > or = 0.5 x 10(9)/L were 11 and 13 days, respectively. Nonhematologic toxicity was moderate. Twenty-nine patients were alive in remission after a median follow-up duration of 6 months (range, 1 to 18). Of 22 patients autografted with t(14;18)-positive harvests, 11 had PCR-detectable cells in bone marrow and/or peripheral blood as long as 16 months posttransplantation. In contrast, six patients became PCR-negative between 3 and 16 months after reinfusion. Follow-up examinations with PCR data for the remaining five patients are not yet available.

CONCLUSION

Conversion to PCR negativity in patients autografted with PCR-positive harvests suggests that the myeloablative regimen is effective and that any reinfused t(14;18)-positive cells may not be sustained. Because conventional chemotherapy provides no cure, we believe that high-dose therapy including total-body irradiation (TBI) should be explored in these particularly radiosensitive lymphomas.

Single-step affinity purification, partial structure and properties of human platelet cGMP inhibited cAMP phosphodiesterase

The human platelet cilostamide- and cGMP-inhibited cAMP phosphodiesterase (cGI-PDE) was rapidly purified approximately 19,000-fold to apparent homogeneity using single step affinity chromatography on the isothiocyanate derivative of cilostamide coupled to aminoethyl agarose. Within 24 h, 30 micrograms of enzyme protein was obtained from 20 ml of packed platelets. Vmax for cAMP and cGMP was 6.1 and 0.9 mumol/min per mg protein, respectively. Several polypeptides (110/105, 79, 62, 55/53 kDa) were identified after SDS-PAGE, all of which were immunologically related to cGI-PDE and represented approx. 5, 20, 50 and 20% of the total protein, respectively. Limited proteolysis of the cGI-PDE with chymotrypsin produced a major fragment of approximately 47 kDa (and at least two smaller peptides) with catalytic activity and sensitivity to cGMP and OPC 3911 similar to controls. Phosphorylation of the cGI-PDE by cAMP-dependent protein kinase (A-kinase) resulted in maximal incorporation of 0.6-1.8 mol of 32P/mol 110/105 and 79 kDa polypeptides; much lower and variable amounts of phosphate were incorporated into the 62 and 55/53 kDa polypeptides. After digestion of cGI-PDE with several proteinases a number of peptides were isolated and sequenced. Most of the peptide sequences obtained could be aligned within the carboxy terminal domain of the deduced sequence of the human cardiac cGI-PDE. These and other results suggest that the subunit size of the intact platelet cGI-PDE is 110 kDa and that proteolytic fragments of 79, 62 and 55/53 kDa are produced during purification. The smaller fragments (62 and 55/53 kDa) contain the catalytic domain; the larger fragments (110 and 79 kDa) also contain the regulatory domain with phosphorylation sites for A-kinase.

Detection of chimeric BCR-ABL genes on bone marrow samples and blood smears in chronic myeloid and acute lymphoblastic leukemia by in situ hybridization

The presence of BCR-ABL fusion genes has important diagnostic and prognostic implications in chronic myeloid leukemia (CML) and acute lymphoblastic leukemia (ALL). The CML-specific chimeric BCR-ABL gene with a break involving the major breakpoint cluster region (M-bcr) of the BCR-gene has been detected by means of fluorescence in situ hybridization (FISH). In this study, we present a FISH protocol that allows the detection of breaks in both the major and the minor breakpoint cluster region (m-bcr). Three hybridization signals of D107F9, a yeast artificial chromosome (YAC)-derived probe spanning the breakpoint regions of the BCR gene, were indicative of the translocation events. To increase the specificity further, this probe was combined with cos-abl 8, a cosmid probe flanking the breakpoint within the ABL gene for dual-color hybridization. Samples of 21 patients with CML, the ALL-derived cell line SUP-B15, and of seven patients with Philadelphia chromosome (Ph1)-positive ALL (three of them with breakpoints within m-bcr) were examined. BCR-ABL fusion was detected in all cases with high specificity (false-positive nuclei: mean, 0.1%). On cytogenetic preparations, the percentages of BCR-ABL-positive interphase cells ranged from 53% to 91%. Comparable efficiencies were achieved on blood smears. In conclusion, hybridization with D107F9 and cos-abl 8 allows unambiguous diagnosis of BCR-ABL genes and is likely to become an important tool for the monitoring of therapies in patients with CML and ALL.

The role of cysteine 78 in fluorosulfonylbenzoyladenosine inactivation of rat liver S-adenosylhomocysteine hydrolase

Inactivation of rat liver S-adenosylhomocysteine hydrolase by the site-directed reagent 5'-p-fluorosulfonylbenzoyladenosine (FSBA) is associated with the formation of a disulfide bond between Cys-78 and Cys-112 (Takata, Y., and Fujioka, M. (1984) Biochemistry 23, 4357-4362; Gomi, T., Ogawa, H., and Fujioka, M. (1986) J. Biol. Chem. 261, 13422-13425). To characterize the inactivation mechanism more precisely, the properties of four hydrolase proteins mutated at Cys-78 or Cys-112 were compared to those of the wild-type enzyme. When Cys-78 was mutated to either a serine or an alanine, proteins with greatly reduced enzymatic activity were obtained, large effects on kinetic constants were observed, and enzymatic activity was not affected by incubation with FSBA. When Cys-112 was mutated to either a serine or an alanine, the activity was similar to the wild-type protein, only small changes in the kinetic constants were observed, and the enzyme was inactivated more rapidly upon incubation with FSBA. FSBA inactivation of the C112A mutant protein was accompanied by the formation of a disulfide between Cys-78 and Cys-52. The data indicate that FSBA initially reacts with Cys-78 and that Cys-78 has an important role in the structure of the enzyme.

A 127 kDa component of a UV-damaged DNA-binding complex, which is defective in some xeroderma pigmentosum group E patients, is homologous to a slime mold protein

A cDNA which encodes a approximately 127 kDa UV-damaged DNA-binding (UV-DDB) protein with high affinity for (6-4)pyrimidine dimers [Abramic', M., Levine, A.S. & Protic', M., J. Biol. Chem. 266: 22493-22500, 1991] has been isolated from a monkey cell cDNA library. The presence of this protein in complexes bound to UV-damaged DNA was confirmed by immunoblotting. The human cognate of the UV-DDB gene was localized to chromosome 11. UV-DDB mRNA was expressed in all human tissues examined, including cells from two patients with xeroderma pigmentosum (group E) that are deficient in UV-DDB activity, which suggests that the binding defect in these cells may reside in a dysfunctional UV-DDB protein. Database searches have revealed significant homology of the UV-DDB protein sequence with partial sequences of yet uncharacterized proteins from Dictyostelium discoideum (44% identity over 529 amino acids) and Oryza sativa (54% identity over 74 residues). According to our results, the UV-DDB polypeptide belongs to a highly conserved, structurally novel family of proteins that may be involved in the early steps of the UV response, e.g., DNA damage recognition.

Interaction of hepatic microsomal epoxide hydrolase derived from a recombinant baculovirus expression system with an azarene oxide and an aziridine substrate analogue

A recombinant baculovirus (vEHX) encoding rat hepatic microsomal epoxide hydrolase has been constructed. Infection of Spodoptera frugiperda (Sf9) cells with the recombinant virus results in the expression of the enzyme at a level estimated to be between 5% and 10% of the cellular protein. The enzyme, which can be purified in 15% yield by a simple three-step procedure involving detergent extraction, DEAE-cellulose chromatography, and removal of the detergent on hydroxylapatite, has physical and kinetic properties very close to those of the enzyme obtained from rat liver microsomes. The interaction of the enzyme with two nitrogen-containing analogues of the substrate phenanthrene 9,10-oxide (1) was investigated in order to delineate the contributions of the oxirane group and the hydrophobic surface of the substrate to substrate recognition. The enzyme exhibits altered kinetic properties toward 1,10-phenanthroline 5,6-oxide (2) in which the biphenyl group of 1 is replaced with a bipyridyl group, suggesting that hydrophobic interaction between the complementary surfaces of the substrate and active site has an influence on catalysis. The conjugate acid of the aziridine analogue of 1, phenanthrene 9,10-imine (3), in which the oxirane oxygen is replaced with NH, has a pKa of 6.1, which allows the characterization of both the neutral and protonated aziridine (3H+) as substrate analogues for the enzyme. The pH dependence of the solvolysis reveals that 3H+ rearranges to a 65/35 mixture of 9-aminophenanthrene and 9-amino-10-hydroxy-9,10-dihydrophenanthrene 10(3)-fold faster than does 3. The neutral aziridine is a competitive inhibitor (Ki = 26 microM) of the enzyme at pH 8.(ABSTRACT TRUNCATED AT 250 WORDS)

Frog secretions and hunting magic in the upper Amazon: identification of a peptide that interacts with an adenosine receptor

A frog used for "hunting magic" by several groups of Panoan-speaking Indians in the borderline between Brazil and Peru is identified as Phyllomedusa bicolor. This frog's skin secretion, which the Indians introduce into the body through fresh burns, is rich in peptides. These include vasoactive peptides, opioid peptides, and a peptide that we have named adenoregulin, with the sequence GLWSKIKEVGKEAAKAAAKAAGKAALGAVSEAV as determined from mass spectrometry and Edman degradation. The natural peptide may contain a D amino acid residue, since it is not identical in chromatographic properties to the synthetic peptide. Adenoregulin enhances binding of agonists to A1 adenosine receptors; it is accompanied in the skin secretion by peptides that inhibit binding. The vasoactive peptide sauvagine, the opioid peptides, and adenoregulin and related peptides affect behavior in mice and presumably contribute to the behavioral sequelae observed in humans.

The gene encoding a Prevotella loescheii lectin-like adhesin contains an interrupted sequence which causes a frameshift

We cloned and sequenced the Prevotella loescheii gene plaA, which encodes a lectin-like adhesin that mediates the coaggregation of P. loescheii 1295 with Streptococcus oralis 34. A probe derived from the N-terminal amino acid sequence of the purified adhesin was used to identify the plaA gene from a P. loescheii genomic library constructed in lambda GEM-11. Sequence analysis of plaA indicates that the initial translation product contains a 22-amino-acid leader. The reading frame of the plaA gene is interrupted after amino acid 28 of the mature protein by a TAA termination codon. Amplification of the P. loescheii genomic DNA in the region surrounding this codon by the polymerase chain reaction followed by DNA sequencing of the cloned DNA fragment established that this stop codon was not an experimental artifact. A frameshift beginning 29 bp downstream of the ochre terminator was required to access the only large open reading frame in the gene. Amino acid sequences of six purified peptides derived by limited proteolysis of adhesin with endoproteinase Lys-C matched the downstream amino acid sequence derived by translation of the large open reading frame. The gene coding sequence of 2.4 kb contains sufficient information for the synthesis of an 89-kDa protein. A putative rho-independent terminator (delta G = -25.5 kcal/mol [ca. -107 kJ/mol]) was detected 38 bp downstream from the plaA stop codon.

Analysis of promoter activity and 5' genomic structure of the neural cell adhesion molecule L1

To gain insight into the molecular mechanisms underlying the regulation of expression of the neural cell adhesion molecule L1 and into the exon-intron structure of the L1 gene, a genomic clone from the mouse was characterized. The clone was identified by screening an EMBL3 library with an L1-specific cDNA probe and comprises approximately 15 kb, in which the first 2,206 nucleotides of the coding region are included. Of the 5 of 6 immunoglobulin (Ig)-like domains sequenced, all are encoded by 2 exons, with the first exon being smaller than the second. The exon encoding the signal peptide is separated from a mini-exon containing 15 bp by a large intron, approximately 2.6 kb in length, whereas the other introns are smaller, with the coding information for the Ig-like domains 3-5 clustered in a 1,643-bp-long fragment with introns only 110-217 bp in length. The 5' upstream region of the clone comprises 5 kb, with the first 112 bp lying upstream to the coding sequence and containing a start site for transcription. No consensus sequence for a TATA box was found. Consensus DNA sequences for the binding of the gene products of Hox 1.3, engrailed and bicoid, are localized upstream to the transcription start site. A 1,262-bp fragment containing part of the first exon showed promoter activity in neuroblastoma cells, but hardly in L cells and not in CHO cells, indicating that this fragment is sufficient for neural cell directed promoter activity.

Molecular cloning and expression of human myocardial cGMP-inhibited cAMP phosphodiesterase

We have cloned a cDNA for a myocardial cGMP-inhibited cAMP phosphodiesterase (cGI PDE) from a human heart cDNA library in lambda Zap II. The open reading frame [3.5 kilobases (kb)] of cDNA clone n.13.2 (7.7 kb) encodes a protein of 125 kDa. In Northern blots of total human ventricle RNA, a single mRNA species (8.3 kb) hybridized with a 4-kb EcoRI restriction fragment of clone n.13.2 cDNA (containing the entire open reading frame). The carboxyl-terminal region of the deduced amino acid sequence of the cGI PDE contains the putative catalytic domain conserved among mammalian PDE families. A partial cDNA clone, n.2, encoding a truncated, 54-kDa cGI PDE containing the conserved domain was expressed as a catalytically active fusion protein in Escherichia coli. cAMP hydrolytic activity was inhibited by cGMP and OPC 3911 but not by rolipram. Thus, this report provides direct proof that the conserved domain contains the catalytic core of cGI PDEs.

Astrocyte-derived TGF-beta 2 and NGF differentially regulate neural recognition molecule expression by cultured astrocytes

Because of the importance of neural recognition molecules expressed by glial cells to mediate interactions with neurons, growth factors and cytokines known to be functional during morphogenesis and in diseases of the nervous system were studied for their effects on recognition molecule expression by cultured immature and mature astrocytes from several brain regions. In cultures of immature astrocytes, transforming growth factors-beta 1 (TGF-beta 1) and -beta 2 (TGF-beta 2) and nerve growth factor (NGF) increased expression of the neural adhesion molecule L1, leading to a glia-mediated L1-specific increase in neurite outgrowth of dorsal root ganglion neurons on the astrocyte substrate. L1 expression induced by TGF-beta was inhibited by addition of antibodies to NGF, suggesting that TGF-beta influences L1 expression by modulating production of NGF by astrocytes. TGF-beta 1 and -beta 2 decreased expression of N-CAM by immature astrocytes. Since N-CAM expression was not affected by NGF and antibodies to NGF did not abolish the TGF-beta-induced decrease in N-CAM expression, NGF did not appear to be the mediator for regulating expression of N-CAM. Expression of the adhesion molecule on glia (AMOG) was not affected by any factor. NGF and TGF-beta 2 in latent form, but not TGF-beta 1 were found in the culture supernatants. Addition of interferon-gamma (IFN-gamma), interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), platelet-derived growth factor (PDGF), or basic fibroblast growth factor (bFGF) to the cultures did not change recognition molecule expression. REcognition molecule expression by mature astrocytes was not found to be modified by any of the factors tested. In view of the observation that levels of L1 and N-CAM expression correlated with the presence of TGF-beta 2 and NGF in the culture supernatants of immature astrocytes, an autocrine regulatory mechanism for recognition molecule expression by these cells is suggested to play a crucial role in regulation of neuron-glia interactions.

Identification of a nucleotide-binding site on glycoprotein IIb. Relationship to ADP-induced platelet activation

Formalin-fixed platelets have been used to study the binding of adenine nucleotides in order to avoid the complications of nucleotide metabolism and to achieve steady-state binding. Sp-adenosine-5'-(1-thiotriphosphate) (Sp-ATP-alpha-S) binds to platelets at two sites (Kd1 3 nM; 31,000 sites/platelet; Kd2 200 nM; 300,000 sites/platelet) as compared with values for ADP under these conditions (Kd1 30 nM; 25,000 sites/platelet and Kd2 3 microM; 400,000 sites/platelet) (bound/total approximately 0.1). Competition binding experiments showed that both of the ATP-alpha-S sites were accessible to ADP and vice versa. [35S]ATP-alpha-S was photoaffinity cross-linked to unfixed platelets by direct irradiation with ultraviolet light. A single radiolabeled component (120 kDa) was identified and shown to be identical with the alpha subunit of GPIIb based on two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by Western blotting with anti-GPIIb monoclonal antibodies, by isoelectric focusing (pI 4.5-5.5), by immunoaffinity adsorption using monoclonal anti-GPIIb/IIIa antibodies coupled to Sepharose, and by crossed immunoelectrophoresis. Amino-terminal sequencing of a tryptic fragment labeled with [35S]ATP-alpha-S identified an 18-kDa domain beginning at Tyr-198 in the primary sequence of GPIIb alpha. These studies demonstrate the presence of an adenine nucleotide-binding site on GPIIb alpha.

Immunoprecipitation of adenylate cyclase with an antibody to a carboxyl-terminal peptide from Gs alpha

An antibody (RM) raised against the carboxyl-terminal decapeptide of the alpha subunit of the stimulatory guanine nucleotide regulatory protein (Gs alpha) has been used to study the interaction of Gs alpha with bovine brain adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1]. RM antibody immunoprecipitated about 60% of the solubilized adenylate cyclase preactivated with either GTP-gamma-S or AlF4-. In contrast, RM antibody immunoprecipitated about 5% of the adenylate cyclase not preactivated (control) and 15% of the adenylate cyclase pretreated with forskolin. Adenylate cyclase solubilized from control membranes or GTP-gamma-S preactivated membranes was partially purified by using forskolin-agarose affinity chromatography. The amount of Gs alpha protein in the partially purified preparations was determined by immunoblotting with RM antibody. There was 3-fold more Gs alpha detected in partially purified adenylate cyclase from preactivated membranes than in the partially purified adenylate cyclase from control membranes. Partially purified adenylate cyclase from preactivated membranes was immunoprecipitated with RM antibody and the amount of adenylate cyclase activity immunoprecipitated (65% of total) corresponded to the amount of Gs alpha protein immunoprecipitated. Only 15% of the partially purified adenylate cyclase from control membranes was immunoprecipitated. The presence of other G proteins in the partially purified preparations of adenylate cyclase was investigated by using specific antisera that detect Go alpha, Gi alpha, and G beta. The G beta protein was the only subunit detected in the partially purified preparations of adenylate cyclase and the amount of G beta was about the same in adenylate cyclase from preactivated membranes and from control membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

Linkage of a gene for neural cell adhesion molecule, L1 (CamL1) to the Rsvp region of the mouse X chromosome

L1 is a glycoprotein with an apparent molecular weight of 200 kDa in the developing fetus and adult central nervous system. In the peripheral nervous system, it has a molecular weight of 230 kDa. The L1 protein appears to be encoded by a single gene that has been located on the human X chromosome by in situ hybridization. In this paper we describe restriction variation in genomic DNA Southern analysis between Mus species for the K13 cDNA probe for the L1 neural cell adhesion molecule. We have designated the locus described by this variation as cell adhesion molecule L1, CamL1. The X chromosome linkage and the relative position on the X chromosome coincident with the genes Rsvp/G6pd/Cf-8 were defined in backcross matings involving M. spretus and M. musculus.

The gene encoding L1, a neural adhesion molecule of the immunoglobulin family, is located on the X chromosome in mouse and man

The murine and human genes for the L1 neural adhesion molecule were shown to lie on conserved regions of the X chromosome to which genes responsible for several neuromuscular diseases have been mapped and which are adjacent to the fragile site (FRAXA) associated with mental retardation. By pulsed-field gel mapping we have demonstrated physical linkage between the L1 gene and other genes located in Xq28: L1 lies between the eye pigment RCP, GCP locus and the glucose-6-phosphate dehydrogenase (G6PD) gene. This location is compatible with the implication of the L1 molecule in one of the X-linked neuromuscular diseases mapped to this region.

Characterization of tissue plasminogen activator binding proteins isolated from endothelial cells and other cell types

Human tissue plasminogen activator (t-PA) was shown to bind specifically to human osteosarcoma cells (HOS), and human epidermoid carcinoma cells (A-431 cells). Crosslinking studies with DTSSP demonstrated high molecular weight complexes (130,000) between 125I-t-PA and cell membrane protein on human umbilical vein endothelial cells (HUVEC), HOS, and A-431 cells. A 48-65,000 molecular weight complex was demonstrated after crosslinking t-PA peptide (res. 7-20) to cells. Ligand blotting of cell lysates which had been passed over a t-PA affinity column revealed binding of t-PA to 54,000 and 95,000 molecular weight proteins. Several t-PA binding proteins were identified in immunopurified cell lysates, including tubulin beta chain, plasminogen activator inhibitor type 1 and single chain urokinase.

The adhesion molecule on glia (AMOG) is a homologue of the beta subunit of the Na,K-ATPase

AMOG (adhesion molecule on glia) is a Ca2(+)-independent adhesion molecule which mediates selective neuron-astrocyte interaction in vitro (Antonicek, H., E. Persohn, and M. Schachner. 1987. J. Cell Biol. 104:1587-1595). Here we report the structure of AMOG and its association with the Na,K-ATPase. The complete cDNA sequence of mouse AMOG revealed 40% amino acid identity with the previously cloned beta subunit of rat brain Na,K-ATPase. Immunoaffinity-purified AMOG and the beta subunit of detergent-purified brain Na,K-ATPase had identical apparent molecular weights, and were immunologically cross-reactive. Immunoaffinity-purified AMOG was associated with a protein of 100,000 Mr. Monoclonal antibodies revealed that this associated protein comprised the alpha 2 (and possibly alpha 3) isoforms of the Na,K-ATPase catalytic subunit, but not alpha 1. The monoclonal AMOG antibody that blocks adhesion was shown to interact with Na,K-ATPase in intact cultured astrocytes by its ability to increase ouabain-inhibitable 86Rb+ uptake. AMOG-mediated adhesion occurred, however, both at 4 degrees C and in the presence of ouabain, an inhibitor of the Na,K-ATPase. Both AMOG and the beta subunit are predicted to be extracellularly exposed glycoproteins with single transmembrane segments, quite different in structure from the Na,K-ATPase alpha subunit or any other ion pump. We hypothesize that AMOG or variants of the beta subunit of the Na,K-ATPase, tightly associated with an alpha subunit, are recognition elements for adhesion that subsequently link cell adhesion with ion transport.

Sequence of the cloned Escherichia coli K1 CMP-N-acetylneuraminic acid synthetase gene

The Escherichia coli CMP-N-acetylneuraminic acid (CMP-NeuAc) synthetase gene is located on a 3.3-kilobase (kb) HindIII fragment of the plasmid pSR23 which contains the genes for K1 capsule production (Vann, W. F., Silver, R. P., Abeijon, C., Chang, K., Aaronson, W., Sutton, A., Finn, C. W., Lindner, W., and Kotsatos, M. (1987) J. Biol. Chem. 262, 17556-17562). The CMP-NeuAc synthetase gene expression was increased 10-30-fold by cloning of a 2.7-kb EcoRI-HindIII fragment onto the vector pKK223-3 containing the tac promoter. The complete nucleotide sequence of the gene encoding CMP-NeuAc synthetase was determined from progressive deletions generated by selective digestion of M13 clones containing the 2.7-kb fragment. CMP-NeuAc synthetase is located near the EcoRI site on this fragment as indicated by the detection of an open reading frame encoding a 49,000-dalton polypeptide. The amino- and carboxyl-terminal sequences of the encoded protein were confirmed by sequencing of peptides cleaved from both ends of the purified enzyme. The nucleotide deduced amino acid sequence was confirmed by sequencing several tryptic peptides of purified enzyme. The molecular weight is consistent with that determined from sodium dodecyl sulfate-gel electrophoresis. Gel filtration and ultracentrifugation experiments under nondenaturing conditions suggest that the enzyme is active as a 49,000-dalton monomer but may form aggregates.

Identification of a cDNA clone specific for the neural cell adhesion molecule AMOG

A cDNA clone of the neural cell adhesion molecule AMOG was isolated from a lambda gt10 library constructed from 8-day-old mouse brain poly(A) + RNA with a 17mer oligonucleotide probe designed from a nonapeptide sequence obtained from tryptic peptides of AMOG. The cDNA clone expressed as a fusion protein that is recognized by polyclonal AMOG antibodies; conversely, polyclonal antibodies prepared against the fusion protein react with AMOG. The clone contains the full sequence derived from the nonapeptide. Of all tissues tested, only brain expresses detectable levels of AMOG by ELISA and Northern blot analyses, indicating a high correlation in expression at the protein and mRNA levels. Both brain and astrocytes express a 3 kb long mRNA, which appears to be encoded by a single gene.